Wide Field of View Head-Up Display System

• US 20090201589A1
• Filed: 04/15/2009
• Published: 08/13/2009
• Est. Priority Date: 09/10/2007
• Status: Active Grant

• Current Assignee: Microvision, Inc.
• Original Assignee: Microvision, Inc.
• Inventors: Freeman, Mark O.
• Granted Patent: US 7,777,960 B2
• Time in Patent Office: Days
• US Class Current: 359/630
• CPC Class Codes: G02B 2027/0123 comprising devices increasing the field of view
• CPC Class Codes: G02B 26/10 Scanning systems
• CPC Class Codes: G02B 27/0103 comprising holographic elements
• CPC Class Codes: G02B 3/08 with discontinuous faces, e.g. Fresnel lens diffractive Fresnel lenses G02B5/1876
• CPC Class Codes: G03B 21/60 characterised by the nature of the surface
• CPC Class Codes: H04N 9/3129 scanning a light beam on the display screen scanning a light beam on a screen in displays other than projection devices G09G3/02; scanning systems in general G02B26/10; projectors using laser light sources in general H04N9/3161

Abstract

A projection system, such as a system suitable for head-up displays in automobiles, includes a laser projection source (101) and a scanner (102). Light from the laser projection source (101) is scanned across a projection surface (104), which can be a car'"'"'s windshield. The projection surface (104) includes a buried numerical aperture expander (105) capable of reflecting some light and transmitting other light. The system may also include an image projection source (551) capable of presenting high-resolution images on a sub-region (552) of the projection surface (604) that has a optical relay (650) disposed therein.

Claims

1. A system for providing a head-up display, comprising:

a laser-projection source;

a scanner configured to receive light from the laser-projection source and deliver scanned light to a projection surface as a projected image; and

a control circuit coupled to the scanner and configured to control scanning of the light received from the laser-projection source to form the projected image;

wherein the projection surface comprises an buried numerical aperture expander comprising;

an exit pupil expander; and

a reflective layer disposed on said exit pupil expander;

wherein the exit pupil expander and the reflective layer are disposed within an envelope, the exit pupil expander and the envelope having substantially similar coefficients of refraction;

wherein some of the light impinging on the exit pupil expander may be at least partially reflected by the reflective layer and expanded into a larger output numerical aperture, and some of the light impinging on the exit pupil expander is at least partially transmitted without substantial distortion through said reflective layer.

2. The system of claim 1, wherein the scanner comprises a two-axis vector scanner, further wherein the light received from the laser-projection source comprises visible light.

3. The system of claim 2, wherein the laser-projection source comprises one of a mono-color laser-projection source or a multi-color laser projection source.

4. The system of claim 2, wherein the projected image comprises informational portions and non-informational portions, wherein the control circuit is configured to cause the scanner to scan the light received from the laser-projection source along the informational portions without scanning the non-informational portions.

5. The system of claim 2, wherein the projection surface comprises a windshield, wherein the projected image appears in a plane defined by the windshield.

6. The system of claim 2, wherein the scanner is configured to deliver the scanned light with a scan angle of at least twenty degrees by twenty degrees.

7. The system of claim 6, wherein a field of view corresponding to the projected image is at least twenty degrees by ten degrees.

8. The system of claim 1, wherein the laser-projection source comprises a plurality of lasers.

9. The system of claim 1, wherein the projection surface further comprises an optical relay disposed along a sub-region of the projection surface.

10. The system of claim 9, wherein the optical relay comprises:

a diffractive optical element having an at least partially reflective coating and having a first index of refraction; and

a filler medium having a second index of refraction and being disposed adjacent to the diffractive optical element;

wherein the optical relay is at least partially transparent.

11. The system of claim 10, wherein the diffractive optical element further comprises:

a first layer and a second layer;

wherein the diffractive optical element and the filler medium are disposed between the first layer and the second layer.

12. The system of claim 10, wherein the diffractive optical element comprises a surface relief computer generated hologram, or a surface relief diffractive lens, or combinations thereof.

13. The system of claim 9, further comprising an image projection source configured to project a second projected image along the sub-region of the projection surface.

14. The system of claim 13, wherein the control circuit is configured to cause the scanner to scan the light received from the laser-projection source along portions of the projection surface other than the sub-region of the projection surface.

15. The system of claim 14, wherein the buried numerical aperture expander is configured to reflect the projected image so as to appear viewable in a plane defined by the projection surface, wherein the optical relay is configured to reflect the second projected image so as to appear viewable in front of the plane defined by the projection surface.

16. The system of claim 13, wherein the image projection source comprises a MEMS scanning source.

17. A projection system, comprising:

a visible laser projection source;

a scanner configured to selectively deflect light received from the visible laser projection source along a projection surface so as to form a projected image; and

the projection surface, wherein the projection surface comprises an aperture expander onto which the projected image is projected to allow a viewer to view the projected image on the aperture expander.

18. The projection system of claim 17, wherein the aperture expander comprises:

an exit pupil expander; and

a reflective layer disposed on the exit pupil expander;

wherein some of the light impinging on the exit pupil expander may be at least partially reflected by the reflective layer and expanded into a larger output numerical aperture, and some of the light impinging on the exit pupil expander is at least partially transmitted without substantial distortion through the reflective layer.

19. The projection system of claim 17, further comprising an image projection source configured to project a second image on a sub-portion of the projection surface, wherein the sub-portion of the projection surface comprises an optical relay onto which the second image is projected to allow the second image to appear to the viewer to be farther away than the projection surface.

20. The projection system of claim 19, wherein the optical relay comprises a lens having an partially-reflective coating and a first index of refraction, wherein the lens comprises a Fresnel lens, a diffractive lens, or a holographic lens, or combinations thereof, and a filler medium having a second index of refraction and being disposed adjacent to the lens.